it goes farther when hit by a metal bat
You can hit farther with a metal bat.
It depends on how hard you hit it.
a metal bat yes a metal will go farther
Because a baseball is smaller you could hit it farther. This is because with less surface area, there is less friction action on the ball. With less friction acting on the ball, it means less "stuff" is holding the ball back from traveling farther, the baseball can physical travel farther than a softball.
metalMetal baseball bats will most likely go farther. A lot of people believe that wood bats hit farther than BBCOR though
Better technique and becoming stronger
That depends what you are hitting them with, and how hard you are hitting them. If you hit a baseball with a baseball bat and a tennis ball with a baseball bat as hard as you can, the tennis ball would go farther. The tennis ball would go farther in most circumstances if you hit each with the same object and with the same force.